The present invention generally relates to the devices that diagnose joint disorders. Specifically, the present invention provides a non-invasive pain provocative means for diagnosing spinal disorders utilizing vibration. This device was first presented at the Society for Back Pain Research on Oct. 30, 1992 in London, England.
The functional spinal unit of the spine is innervated with nerve fibers originating in the spinal cord. Two types of peripheral nerve fibers exist; myelinated and unmyelinated. Myelinated nerve fibers sense tissue or joint position and pressure. Therefore, they are mechanical receptors. Unmyelinated nerve fibers are mainly chemical and nociceptor receptors. By stimulating these nerve fibers, pain can be provoked.
The knowledge gained from disc innervation has changed the earlier concepts of the production of low back pain. Today nerve root compression is not regarded as the only source of such pain but it may also be attributable to intradiscal ruptures of the annulus, which have been found in many different lumbar syndromes. However, there is no simple tool available for the identification of these intradiscal ruptures in the patients examined, and can thus not be distinguished from other causes of back pain. The only possible method is discography that has to be performed under fluoroscopy which is laborious and expensive. In addition, it is not feasible for discography to be performed in everyday medical practice. A normal disc is painless in discography, but a close correlation has been found between annular rupture of a disc and reproduction of clinical pain.
Discography may be the most controversial diagnostic procedure for patients with low back pain. It involves the injection of radiographic contrast into the nucleus of an intervertebral disc. During the injection, the physician performing the procedure asks the patient if the injection generates pain similar to his/her "usual pain." This method of pain provocation is the only method at this time that can differentiate which disc is responsible for a patient's symptoms. However, discography requires premedication, x-ray control with needle injections, and a possibility of developing discitis. A non-invasive method of differentiating which disc is responsible for a patient's symptoms is needed.
Many radiographic diagnostic tools are used by the physician including plain radiographs, computer tomography scans, magnetic resonance imaging, bone scans, and myelograms. These tools image the spine and show potential sources of pain, but do not pinpoint the place of pain origin. Also, these tests demonstrate abnormalities in persons without pain, thus making pain provocation even more important.
Prior art for this device takes two forms, spinal diagnostic devices and devices for the spine utilizing vibration. U.S. Pat. No. 4,723,557 discloses a lordosimeter to diagnose lordosis and scoliosis. U.S. Pat. No. 4,476,873 discloses an ultrasound imaging system for scoliosis diagnosis. These two patents disclose methods and devices to diagnose spinal disorders that involve spinal misalignment. Whereas, the present invention can be used to diagnose the origin of back pain. U.S. Pat. No. 4,266,536 discloses a massaging device capable of being used by the person receiving the massage. U.S. Pat. No. 4,230,098 discloses a traction device capable of treatment with vibration. U.S. Pat. No. 4,347,838 discloses a foot massager with a special spinal roller attachment. All of the above patents treat the muscles of the back with a massaging action providing benefit and comfort. Whereas, the present invention uses vibration to provocatively produce pain which can be used to diagnose spinal disorders.